TST: Install `test_requirements` during the container build stage
TST: Install `test_requirements` during the container build stage

mhvk/numpy,anntzer/numpy,numpy/numpy,anntzer/numpy,numpy/numpy,pdebuyl/numpy,anntzer/numpy,charris/numpy,pdebuyl/numpy,mattip/numpy,anntzer/numpy,mattip/numpy,mattip/numpy,mattip/numpy,endolith/numpy,charris/numpy,pdebuyl/numpy,endolith/numpy,numpy/numpy,mhvk/numpy,charris/numpy,pdebuyl/numpy,endolith/numpy,mhvk/numpy,endolith/numpy,mhvk/numpy,mhvk/numpy,rgommers/numpy,rgommers/numpy,rgommers/numpy,charris/numpy,rgommers/numpy,numpy/numpy